Invertebrates
Tsetse Fly
Glossina spp. · also called tsetse flies
A tsetse fly settles onto its host with wings folded neatly over its back, feeding on blood in a way both male and female flies rely on throughout their lives. Its own offspring, when they eventually arrive, will not hatch from an egg at all, but be born fully formed, one at a time, after developing internally.
Overview
The tsetse fly, genus Glossina, is a blood-feeding insect native to savanna and forest habitat across sub-Saharan Africa. Its unusual live-birth reproductive strategy and role as a vector for African trypanosomiasis make it one of the more medically and ecologically significant fly groups in the world.
A slow but resilient reproductive strategy
Rather than producing large numbers of eggs like most insects, the tsetse fly invests heavily in a single offspring at a time, a strategy that trades speed for a genuinely improved chance of individual larval survival.
Status
Least Concern — present across suitable habitat throughout sub-Saharan Africa, with control efforts focused on disease prevention rather than population conservation.
Tsetse Fly: common questions
Why does the tsetse fly give birth instead of laying eggs?
A tsetse fly gives birth to a single, fully developed larva at a time rather than laying a large number of eggs, an unusual reproductive strategy called adenotrophic viviparity that nourishes the developing larva internally before birth, a rare approach among insects that trades a low reproductive rate for improved offspring survival.
What disease does the tsetse fly spread?
The tsetse fly can transmit parasites responsible for African trypanosomiasis, a serious disease affecting both humans, known as sleeping sickness, and livestock, known as nagana, across parts of the fly's sub-Saharan African range, making it a significant public health and agricultural concern in affected regions.
Do both male and female tsetse flies bite?
Yes, unlike many blood-feeding insects in which only females feed on blood, both male and female tsetse flies feed exclusively on vertebrate blood throughout their adult lives, a trait that distinguishes the group from mosquitoes, in which typically only females require a blood meal.
Where is the tsetse fly found?
Tsetse fly species are native to savanna, woodland, and forest habitat across parts of sub-Saharan Africa, generally in areas providing suitable shade and proximity to the host animals the flies depend on for their blood meals.